Method for transferring from a mold a hydrophobic top coat onto an optical substrate

ABSTRACT

The invention relates to a method for forming from a mold optical articles. These methods are particularly useful in forming ophthalmic articles such as ophthalmic lenses, having a hydrophobic top coat thereon. Ophthalmic articles produced by these methods are also part of the invention.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to U.S. Provisional ApplicationSerial No. 60/294,425 filed May 29, 2001.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates to a method for forming from a moldoptical articles, in particular ophthalmic articles such as ophthalmiclenses, having a hydrophobic top coat thereon.

[0004] 2. Previous Art

[0005] It is a common practice in the art to coat at least one face ofan ophthalmic lens with several coatings for imparting to the finishedlens additional or improved optical or mechanical properties. Thus, itis usual practice to coat at least one face of an ophthalmic lenssubstrate typically made of an organic glass material with successively,starting from the face of the substrate, an impact-resistant coating(impact-resistant primer), a scratch-resistant coating (hard coat), ananti-reflecting coating and a hydrophobic top coat.

[0006] Typically, optical articles made of organic glass materials areformed in a mold comprising two separate parts having optical surfaceswhich, when the two-parts are assembled, define a molding cavity. Aliquid curable composition is then introduced in the molding cavity andcured to form the optical article. The optical article is thereafterrecovered upon disassembling of the mold parts.

[0007] Examples of typical two-part molds and molding methods aredisclosed in U.S. Pat. No. 5,547,618 and 5,662,839.

[0008] It is known in the art to also apply a scratch-resistant coatingcomposition on the optical surfaces of the parts of a two-part mold, andif necessary precure it, assemble the mold parts, fill the moldingcavity with an optical liquid curable material, cure the opticalmaterial and disassemble the mold parts to recover the molded opticalarticle having a scratch-resistant coating deposited and adheredthereon.

[0009] Such a method is, for example, disclosed in document EP-102847.

[0010] U.S. Pat. No. 5,096,626 discloses a method for making an opticalarticle having a scratch-resistant coating and/or an anti-reflectingcoating thereon, which comprises:

[0011] forming an anti-reflecting coating and/or a scratch-resistantcoating onto the optical surfaces of a two-part mold;

[0012] assembling the two-part mold;

[0013] pouring an optical liquid curable composition in the moldingcavity;

[0014] curing the optical composition, and

[0015] disassembling the two-part mold for recovering the molded opticalarticle having a scratch-resistant coating or a scratch-resistantcoating and an anti-reflecting coating thereon;

[0016] wherein, either at least one release agent is incorporated intothe scratch-resistant coating or a film of at least one release agent isformed on the optical surfaces of the mold parts, prior to the formationof the anti-reflecting coating and/or the scratch-resistant coating.

[0017] The preferred release agents useful in the method of U.S. Pat.No. 5,096,626 are fluorosilicones, fluoroalkyalkoxysilanes and mixturesthereof.

[0018] U.S. Pat. No. 5,160,668 discloses a method for transferring ananti-reflecting coating onto a surface of an optical element whichcomprises:

[0019] forming on the optical surface of a part of a two-part mold arelease layer of a water soluble inorganic salt;

[0020] forming on said release layer an anti-reflecting layer,

[0021] assembling the mold parts;

[0022] pouring a liquid optical curable composition in the moldingcavity,

[0023] curing the optical composition,

[0024] disassembling the mold parts and dissolving the release layer inwater to recover the coated optical element.

[0025] U.S. Pat. No. 5,733,483 discloses a method for forming on-sitetinted and coated optical elements from a mold which comprises:

[0026] forming successively on an optical surface of at least one partof a two-part mold, a polymer release layer, an anti-reflecting coatinglayer, a coupling agent layer and a hard coat layer;

[0027] assembling the two-part mold;

[0028] pouring an optical liquid curable material in the molding cavity;

[0029] curing the optical material and the anti-reflecting, couplingagent and hard coat layers; and

[0030] disassembling the mold parts to recover the coated opticalelement.

[0031] The polymer release layer can be made of a water soluble polymersuch as polyvinylic acid (PAA), polyethylene-oxide (PEO),poly(N-vinylpyrolidone) (PNVP), polyvinylalcohol (PVA) or polyacrylamid(PAM); a non-water soluble and UV curable polymer such aspolybutadiene-diacrylate (PBD-SA), polyethyleneglycol-diacrylate(PEG-DA) or a highly crosslinked acrylate, and commercial mold releaseagents such as Dow-Corning 20 Release.

[0032] The coupling agent layer generally comprises a(meth)acryloxyalkyltrialkoxysilane. This coupling agent layer is used inorder to better extract the anti-reflecting coating from the mold.

[0033] Hydrophobic top coats are classically used for improving dirtymark resistance of finished optical articles, in particular opticalarticles comprising an anti-reflecting coating.

[0034] A problem associated with these hydrophobic top coats is theirtendency to poorly adhere on the optical substrate and in particular onthe anti-reflecting coating of a coated optical substrate.

[0035] What is needed is a method which will provide easy transfer froma mold of a hydrophobic top coat onto an optical substrate, inparticular onto the anti-reflecting coating of a coated opticalsubstrate as well as an improved adhesion of the hydrophobic top coatonto the optical substrate and in particular onto the anti-reflectingcoating of a coated optical substrate.

SUMMARY OF THE INVENTION

[0036] It is an object of this invention to provide a method for easilytransferring a hydrophobic top coat from a mold onto an opticalsubstrate.

[0037] It is an additional object of this invention to provide a methodfor easily transferring a hydrophobic top coat from a mold onto theanti-reflecting coating of a coated optical substrate.

[0038] It is a further object of this invention to provide a method asabove which provides improved adhesion of the hydrophobic top coat ontoan optical substrate and in particular onto an anti-reflecting coatingof a coated optical substrate.

[0039] In accordance with the above objects and those that will bementioned and will become apparent below, the method for transferring ahydrophobic top coat onto an optical substrate comprises:

[0040] providing a two-part plastic mold having opposed optical surfacesdefining therebetween a molding cavity;

[0041] forming on at least one of the optical surfaces of the mold, ahydrophobic top coat;

[0042] filling the molding cavity with an optical substrate liquidcurable composition;

[0043] curing the liquid curable composition, and

[0044] disassembling the two-part mold for recovering an optical articlecomprising an optical substrate having deposited and adhered on at leastone of its faces, a hydrophobic top coat.

[0045] In a preferred embodiment, the plastic mold is made ofpolycarbonate or polynorbornene.

[0046] To further improve release of the coated optical article from themold, a release agent can be incorporated in the plastic material of themold, or the optical surfaces of the mold parts can be coated with arelease agent layer.

[0047] In a further preferred embodiment, the method according to theinvention comprises, prior to filling the mold with the opticalsubstrate composition, forming onto the hydrophobic top coat ananti-reflecting coating and optionally forming, in the indicated order,a scratch-resistant coating and/or an impact-resistant primer coating.

[0048] The anti-reflecting coating is typically comprised of amultilayer stack of alternating high and low refractive indicesdielectric materials, generally a mineral oxide, which are preferablyvacuum deposited.

[0049] In the most preferred embodiment, the uppermost layer of thestack (which is the first layer of the anti-reflecting stack directlydeposited onto the hydrophobic top coat) is vacuum deposited using a twostage process.

[0050] In a first stage, a first thin sub-layer is deposited by vacuumevaporation of the appropriate dielectric material, directly on thehydrophobic top coat. In a second stage a second thin sub-layer of thesame dielectric material is deposited on the first sub-layer using anion assisted vacuum deposition process. Preferably, the dielectricmaterial of the first layer is SiO₂.

BRIEF DESCRIPTION OF THE DRAWING

[0051] For the further understanding of the objects and advantages ofthe present invention, reference should be made to the followingdetailed description, taken in conjunction with the accompanyingdrawings, in which like parts are given like reference numerals andwherein:

[0052]FIG. 1A to FIG. 1C schematically illustrate the main steps of anembodiment of the method of the invention.

DETAILED DESCRIPTION OF THE INVENTION

[0053] Although in the following description, only one face of theoptical article is being coated with the optical functional coatingsaccording to the invention, it should be understood that both faces ofthe optical articles can be coated simultaneously using the method ofthe invention.

[0054] With respect to FIG. 1A, there is shown schematically a frontpart 1 of a two-part mold, on the optical surface 1 a of which has beensuccessively formed a hydrophobic top coat 10, an anti-reflectingcoating 20, a scratch-resistant coating 30 and an impact-resistantprimer coating 31.

[0055] The two-part mold used in the method of the invention comprises afront part 1 having an optical surface 1 a and a rear part 2 (FIG. 1B)having an optical surface 2 a.

[0056] Typically the two-parts 1, 2 of the mold are assembled through agasket or an adhesive tape (not shown) so that the optical surfaces 1 a,2 a of the mold parts define therebetween a molding cavity.

[0057] The mold parts 1, 2 are preferably made of a plastic material.

[0058] Among the plastic materials that can be used for the two-partmold there can be cited: polycarbonates (PC), polyamides (PA),polyimides (PI), polysulfones (PS), copolymers ofpolyethyleneterephtalate and polycarbonate (PET-CP), crystalpolyethyleneterephtalate (crystal PET), glass fiber reinforcedpolyethyleneterephtalate, and polyolefins such as polynorbornenes. Thepreferred plastic materials are polycarbonates and polynorbornenes.

[0059] A very good plastic material that can be used for the two partmold is a copolymer having the followings units

[0060] Such copolymer is available from Bayer under the commercial tradename APEC.

[0061] This copolymer has a high rigidity which can be an advantage forthe use as a mold material.

[0062] Preferably, the thickness center for each mold part is at least 4mm.

[0063] To enhance the release effect of the molds, in particular withregard to the hydrophobic top coating, one or more release agents can beincorporated in the polymer material of the mold. Examples of suchrelease agents are trimethylchlorosilane. Chloromethyltrimethylsilane,chloropropyltrimethylsilane, chloromethyldodecyl dimethylsilane,chlorine terminated polydimethyl siloxane, (3,3-dimethylbutyl)dimethylchlorosilane, hexamethyldisilazane, octamethyltetrasilazane,aminopropyldimethyl terminated polydimethylsiloxane, 3-trimethoxysilylpropyloctadecyldimethylammonium chloride, tetradecyldimethyl(3-trimethoxysilylpropyl) ammonium chloride, trimethylethoxysilane andoctadecyltrimethoxysilane.

[0064] If necessary the optical surfaces 1 a, 2 a of the parts of theplastic mold may be previously coated with a protective and/or releasecoating which either protects the optical surfaces from defects such asscratches that may be created during handling. This protective and/orrelease coating may also even the optical surface and/or enhance therelease effect.

[0065] Examples of such coatings are:

[0066] A UV-curable acrylic layer optionally containing at least one ofthe above cited release agent or an amine containing polysiloxane layeroptionally containing at least one of the above release agent;

[0067] A fluorocarbon polymer layer, such as polytetrafluoroethylene(PTFE) polymers, for example Teflon® AF, Teflon® PTFE FEP and Teflon®PTFE PFA;

[0068] A buffer layer which may delaminate from the mold part opticalsurface and from which the top coat can release, such as avacuum-deposited magnesium fluoride (MgF₂) layer or a siloxane basecoating normally used to input scratch resistance to lenses. Both ofthese layers release readily from the optical surface of the mold, inparticular of a polycarbonate mold. After demolding of the opticalarticle, these layers are eliminated.

[0069] The protective and/or release coatings can be deposited by dipcoating or spin coating, and depending upon their technical natures theymay be UV and/or thermally cured or simply dried. Those protectiveand/or release coatings have typically a thickness of 2 nm to 10 μm.

[0070] The mold parts made of plastic material are UV transparent andallow UV and/or thermal curing of the different layers and in particularof the optical substrate composition. Preferably, the polymer materialof the mold parts are free of UV absorber.

[0071] As shown in FIG. 1A, there is first deposited on the opticalsurface 1 a of the first part 1 of, for example, a polycarbonate mold, ahydrophobic top coat composition.

[0072] The hydrophobic top coat 10, which in the finished opticalarticle constitutes the outermost coating on the optical substrate, isintended for improving dirty mark resistance of the finished opticalarticle and in particular of the anti-reflecting coating.

[0073] As known is the art, a hydrophobic top coat is a layer whereinthe stationary contact angle to deionized water is at least 60°,preferably at least 75° and more preferably at least 90°. The stationarycontact angle is determined according to the liquid drop method in whicha water drop having a diameter smaller than 2 mm is formed on theoptical article and the contact angle is measured.

[0074] The hydrophobic top coats preferably used in this invention arethose which have a surface energy of less than 14 m Joules/m².

[0075] The invention has a particular interest when using hydrophobictop coats having a surface energy of less than 13 m Joules/m² and evenbetter less than 12 m Joules/m².

[0076] The surface energy values referred just above are calculatedaccording to Owens Wendt method described in the following document :“Estimation of the surface force energy of polymers” Owens D. K. WendtR. G. (1969) J. Appl. Polym. Sci., 1741-1747.

[0077] Such hydrophobic top coats are well known in the art and areusually made of fluorosilicones or fluorosilazanes i.e. silicones orsilazanes bearing fluor containing groups. Example of a preferredhydrophobic top coat material is the product commercialized by Shin Etsuunder the name KP 801M.

[0078] The top coat 10 may be deposited onto the optical surface 1 a ofmold part 1 using any typical deposition process, but preferably usingthermal evaporation technique.

[0079] Thickness of the hydrophobic top coat 10 usually ranges from 1 to30 nm, preferably 1 to 15 nm.

[0080] Anti-reflecting coatings and their methods of making are wellknown in the art. The anti-reflecting can be any layer or stack oflayers which improves the anti-reflective properties of the finishedoptical article.

[0081] The anti-reflecting coating may preferably consist of a mono- ormultilayer film of dielectric materials such as SiO, SiO₂ Si₃N₄, TiO₂,ZrO₂, Al₂O₃, MgF₂ or Ta₂O₅, or mixtures thereof.

[0082] The anti-reflecting coating can be applied in particular byvacuum deposition according to one of the following techniques:

[0083] 1)—by evaporation, optionally ion beam-assisted;

[0084] 2)—by spraying using an ion beam,

[0085] 3)—by cathode sputtering; or

[0086] 4)—by plasma-assisted vapor-phase chemical deposition.

[0087] In case where the film includes a single layer, its opticalthickness must be equal to λ/4 where λ is wavelength of 450 to 650 nm.

[0088] Preferably, the anti-reflecting coating is a multilayer filmcomprising three or more dielectric material layers of alternativelyhigh and low refractive indexes.

[0089] Of course, the dielectric layers of the multilayeranti-reflecting coating are deposited on the hydrophobic top coat in thereverse order they should be present on the finished optical article.

[0090] In the embodiment shown in FIG. 1A, the anti-reflecting coating20 comprises a stack of four layers formed by vacuum deposition, forexample a first SiO₂ layer 21 having an optical thickness of about 100to 160 nm, a second ZrO₂ layer 22 having an optical thickness of about120 to 190 nm, a third SiO₂ layer 23 having an optical thickness ofabout 20 to 40 nm and a fourth ZrO₂ layer 24 having an optical thicknessof about 35 to 75 nm.

[0091] In order to improve adhesion of the anti-reflecting coating 20onto the hydrophobic top coat 10 and release of the hydrophobic top coat10 from the optical surface 1 a of mold part 1, the SiO₂ layer 21 of theanti-reflecting coating is deposited on the top coat 10 using atwo-stage process.

[0092] In a first stage a first thin sub-layer of SiO₂ is deposited byvacuum evaporation, directly on the hydrophobic material of the topcoat. In a second stage a second thin sub-layer of SiO₂ is deposited onthe first sub-layer using a ion assisted vacuum deposition process.

[0093] The physical thickness of the final SiO₂ layer 21 ranges from 80to 120 nm (optical thickness 100 to 160 nm).

[0094] Using the above two stage process as proved to result in goodadhesion between the top coat and the anti-reflecting coating.

[0095] Preferably, after deposition of the four-layer anti-reflectingstack, a thin layer of SiO₂ 25 of 1 to 50 nm thick, is deposited. Thislayer 25 promotes the adhesion between the anti-reflecting stack and thescratch-resistant coating 30 to be subsequently deposited.

[0096] The next layer to be deposited is the scratch-resistant coating30. Any known optical scratch-resistant coating composition can be usedto form the scratch-resistant coating 30. Thus, the scratch-resistantcoating composition can be à UV and/or a thermal curable composition.

[0097] By definition, a scratch-resistant coating is a coating whichimproves the abrasion resistance of the finished optical article ascompared to a same optical article but without the scratch-resistantcoating.

[0098] Preferred scratch-resistant coatings are those made by curing aprecursor composition including epoxyalkoxysilanes or a hydrolyzatethereof, silica and a curing catalyst. Examples of such compositions aredisclosed in U.S. Pat. No. 4,211,823, WO 94/10230, U.S. Pat. No.5,015,523.

[0099] The most preferred scratch-resistant coating compositions arethose comprising as the main constituents an epoxyalkoxysilane such as,for example, γ-glycidoxypropyltrimethoxysilane (GLYMO) and adialkyldialkoxysilane such as, for example dimethyldiethoxysilane(DMDES), colloidal silica and a catalytic amount of a curing catalystsuch as aluminum acetylacetonate or a hydrolyzate thereof, the remainingof the composition being essentially comprised of solvents typicallyused for formulating these compositions.

[0100] In order to improve the adhesion of the scratch-resistant coating30 to the impact-resistant primer coating 31 to be subsequentlydeposited, an effective amount of at least one coupling agent can beadded to the scratch-resistant coating composition.

[0101] The preferred coupling agent is a pre-condensed solution of anepoxyalkoxysilane and an unsatured alkoxysilane, preferably comprising aterminal ethylenic double bond.

[0102] Examples of epoxyalkoxysilanes areγ-glycidoxypropyltermethoxysilane,γ-glycidoxypropylpentamethyldisiloxane,γ-glycidoxypropylmethyldiisopropenoxysilane,(γ-glycidoxypropyl)methyldiethoxy-silane,γ-glycidoxypropyldimethylethoxysilane,γ-glycidoxypropyl-diisopropylethoxysilane and(γ-glycidoxypropyl)bis(trimethylsiloxy) methylsilane.

[0103] The preferred epoxyalkoxysilane is (y-glycidoxypropyl)trimethoxysilane.

[0104] The unsatured alkoxysilane can be a vinylsilane, an allylsilane,an acrylic silane or a methacrylic silane.

[0105] Examples of vinylsilanes are vinyltris(2-methoxyethoxy)silane,vinyltrisisobutoxysilane, vinyltri-t-butoxysilane,vinyltriphenoxysilane, vinyltrimethoxysilane, vinyltriisopropoxysilane,vinyltriethoxysilane, vinyltriacetoxysilane, vinylmethyldiethoxysilane,vinylmethyldiacetoxy-silane, vinylbis(tlimethylsiloxy)silane andvinyldimethoxyethoxysilane.

[0106] Examples of allylsilanes are allyltrimethoxysilane,alkyltriethoxysilane and allyltris (trimethylsiloxy)silane.

[0107] Examples of acrylic silanes are 3-acryloxypropyltris(trimethylsiloxy) silane, 3-acryloxypropyltrimethoxysilane,acryloxypropylmethyl-dimethoxysilane,3-acryloxypropylmethylbis(trimethylsiloxy) silane,3-acryloxypropyldimethylmethoxysilane,n-(3-acryloxy-2-hydroxypropyl)-3-aminopropyltriethoxysilane.

[0108] Examples of methacrylic silanes are 3-methacryloxypropyltris(vinyldimethoxylsiloxy)silane, 3-methacryloxypropyltris(trimethylsiloxy) silane, 3-methacryloxypropyltris(methoxyethoxy)silane,3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylpentamethyldisiloxane, 3-methacryloxypropylmethyldimethoxysilane,3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyldimethylmethoxysilane, 3-methacryloxypropyldimethylethoxysilane,3-methacryloxypropenyltrime-thoxysilane and 3-methacryloxypropylbis(trimethylsiloxy)methylsilane.

[0109] The preferred silane is acryloxypropyltrimethoxysilane.Preferably, the amounts of epoxyalkoxysilane(s) and unsaturatedalkoxysilane(s) used for the coupling agent preparation are such thatthe weight ratio weight of epoxyalkoxysilane$R = \frac{\text{weight~~of~~epoxyalkoxysilane}}{\text{weight~~of~~unsaturated~~alkoxysilane}}$

[0110] verifies the condition 0.8≦R≦1.2.

[0111] The coupling agent preferably comprises at least 50% by weight ofsolid material from the epoxyalkoxysilane(s) and unsaturatedalkoxysilane(s) and more preferably at least 60% by weight.

[0112] The coupling agent preferably comprises less than 40% by weightof liquid water and/or organic solvant, more preferably less than 35% byweight.

[0113] The expression “weight of solid material from epoxyalkoxy silanesand unsatured alkoxysilanes” means the theoretical dry extract fromthose silanes which is the calculated weight of unit Q_(k) SiO_((4-k)/2)where Q is the organic group that bears the epoxy or unsaturated groupand Q_(k) SiO_((4-k)/2) comes from Q_(k) Si R′O_((4-k)) where SiR′reacts to form SiOH on hydrolysis.

[0114] k is an integer from 1 to 3 and is preferably equal to 1.

[0115] R′ is preferably an alkoxy group such as OCH₃.

[0116] The water and organic solvents referred to above come from thosewhich have been initially added in the coupling agent composition andthe water and alcohol resulting from the hydrolysis and condensation ofthe alkoxysilanes present in the coupling agent composition.

[0117] Preferred preparation methods for the coupling agent comprises:

[0118] 1) mixing the alkoxysilanes

[0119] 2) hydrolysing the alkoxysilanes, preferably by addition of anacid, such as hydrochloric acid

[0120] 3) stirring the mixture

[0121] 4) optionally adding an organic solvent

[0122] 5) adding one or several catalyst(s) such as aluminumacetylacetonate

[0123] 6) stirring (typical duration: overnight).

[0124] Typically the amount of coupling agent introduced in thescratch-resistant coating composition represents 0.1 to 15% by weight ofthe total composition weight, preferably 1 to 10% by weight.

[0125] The scratch-resistant coating composition can be applied on theanti-reflecting coating using any classical method such as spin, dip orflow coating.

[0126] The scratch-resistant coating composition can be simply dried oroptionally precured before application of the subsequentimpact-resistant primer coating 31. Depending upon the nature of thescratch-resistant coating composition thermal curing, UV-curing or acombination of both can be used.

[0127] Thickness of the scratch-resistant coating 30, after curing,usually ranges from 1 to 15 μm, preferably from 2 to 6 μm.

[0128] Before applying the impact resistant primer on the scratchresistant coating, it is possible to subject the surface of the scratchresistant coating to a corona treatment or a vacuum plasma treatment, inorder to increase adhesion.

[0129] The impact-resistant primer coating 31 can be any coatingtypically used for improving impact resistance of a finished opticalarticle. Also, this coating generally enhances adhesion of thescratch-resistant coating 30 on the substrate of the finished opticalarticle.

[0130] By definition, an impact-resistant primer coating is a coatingwhich improves the impact resistance of the finished optical article ascompared with the same optical article but without the impact-resistantprimer coating.

[0131] Typical impact-resistance primer coatings are (meth)acrylic basedcoatings and polyurethane based coatings.

[0132] (Meth)acrylic based impact-resistant coatings are, among others,disclosed in U.S. Pat. No. 5,015,523 whereas thermoplastic andcrosslinked based polyurethane resin coatings are disclosed inter alia,in Japanese Patents 63-141001 and 63-87223, EP-0404111 and U.S. Pat. No.5,316,791.

[0133] In particular, the impact-resistant primer coating according tothe invention can be made from a latex composition such as apoly(meth)acrylic latex, a polyurethane latex or a polyester latex.

[0134] Among the preferred (meth)acrylic based impact-resistant primercoating compositions there can be cited polyethyleneglycol(meth)acrylatebased compositions such as, for example, tetraethyleneglycoldiacrylate,polyethyleneglycol (200) diacrylate, polyethyleneglycol (400)diacrylate, polyethyleneglycol (600) di(meth)acrylate, as well asurethane (meth)acrylates and mixtures thereof.

[0135] Preferably the impact-resistant primer coating has a glasstransition temperature (Tg) of less than 30° C.

[0136] Among the preferred impact-resistant primer coating compositions,there may be cited the acrylic latex commercialized under the nameAcrylic latex A-639 commercialized by Zeneca and polyurethane latexcommercialized under the names W-240 and W-234 by Baxenden.

[0137] In a preferred embodiment, the impact-resistant primer coatingmay also include an effective amount of a coupling agent in order topromote adhesion of the primer coating to the optical substrate and/orto the scratch-resistant coating.

[0138] The same coupling agents, in the same amounts, as for thescratch-resistant coating compositions can be used with theimpact-resistant coating compositions.

[0139] The impact-resistant primer coating composition can be applied onthe scratch-resistant coating 30 using any classical method such asspin, dip, or flow coating.

[0140] The impact-resistant primer coating composition can be simplydried or optionally precured before molding of the optical substrate.Depending upon the nature of the impact-resistant primer coatingcomposition, thermal curing, UV-curing or a combination of both can beused.

[0141] Thickness of the impact-resistant primer coating 31, aftercuring, typically ranges from 0.05 to 20 μm, preferably 0.5 to 10 μm andmore particularly from 0.6 to 6 μm.

[0142] The next step of the method is, as shown in FIG. 1B, assemblingthe front part 1 coated with the hydrophobic top coat, theanti-reflecting, scratch-resistant and impact-resistant primer coatings20, 30, 31 with the rear part 2 of the two-part mold as described, forexample, in U.S. Pat. Nos. 5,547,618 and 5,562,839.

[0143] The molding cavity is then filled with a liquid curable opticalcomposition which is cured to form the optical substrate 40.

[0144] The optical substrate can be made from any typical liquid,curable composition used in the optical field.

[0145] Examples of such optical substrates are substrates resulting fromthe polymerization of:

[0146] diethylene glycol bis (allylcarbonate) based compositions,

[0147] (meth)acrylic monomer based compositions, such as compositionscomprising (meth)acrylic monomers derived from bisphenol-A;

[0148] thio(meth)acrylic monomer based compositions;

[0149] polythiourethane precursor monomer based compositions; and

[0150] epoxy and/or episulfide monomer based compositions.

[0151] Depending upon the nature of the curable optical material, theoptical material can be thermally cured, UV-cured or cured with acombination of both, or cured at ambient temperature.

[0152] As shown in FIG. 1C, once the optical substrate 40 has beencured, and optionally concurrently the scratch-resistant coating 30 andthe impact-resistant primer coating 31 if not previously cured, the moldpart 10, 11 are disassembled to recover the optical substrate 40 havingtransferred on one face, the impact-resistant primer coating 31, thescratch-resistant coating 30, the anti-reflecting coating 20 and thehydrophobic top coat 10.

[0153] The following examples illustrate the present invention. In theexamples, unless otherwise stated, all parts and percentages are byweight.

[0154] 1. Two-Part Mold

[0155] In all the examples the mold used was made of polycarbonate(General Electric Company).

[0156] 2. Hydrophobic Top Coat

[0157] Hydrophobic top coat used in the examples is a fluorosilazanecommercialized by SHIN ETSU under the name KP 801M.

[0158] 3. Scratch-Resistant Coating Compositions (Hard CoatingComposition)

[0159] The following thermal and/or UV curable hard coating compositionswere prepared by mixing the components as indicated hereinunder.Component Parts by weight Hard coating composition n° 1: thermallycurable Glymo 21.42 0.1N HCl 4.89 Colloidal Silica 1034A (35% solid)30.50 Methanol 29.90 Diacetone alcohol 3.24 Aluminum acetylacetonate0.45 Coupling agent 9.00 Surfactant (1/10 dilution) 0.60 Hard coatingcomposition n° 2: thermally curable Glymo 18.6 0.1N HCl 6.62Dimethyldiethoxysilane (DMDES) 9.73 Colloidal Silica/MeOH⁽¹⁾ 60.1Aluminum acetylacetonate 1.2 Methyl Ethyl Ketone (MEK) 3.65 Couplingagent 5.00 Surfactant FC 430⁽²⁾ 0.05 Hard coating composition n° 3:thermally curable Glymo 18.6 0.1N HCl 6.62 Dimethyldiethoxysilane 9.73Colloidal Silica/MeOH⁽¹⁾ 60.1 Aluminum acetylacetonate 1.2 Methyl EthylKetone (MEK) 3.65 Surfactant FC430⁽²⁾ 0.05 Hard coating composition n°4: (UV curable) Glymo 23.75 n-propanol 14.25 Colloidal Silica/MeOH⁽¹⁾47.51 Tyzor DC (1% dilution)⁽³⁾ 14.25 UVI-6974⁽⁴⁾ 0.2735 Coupling agent:precondensed solution of: Glymo 10.0 Acryloxypropyltrimethoxysilane 10.0O.IN HCl 0.5 Aluminum acetylacetonate 0.2 Diacetone alcohol 1.0 ⁽¹⁾SunColloid MA-ST from NISSAN Company (containing 30% by weight of solidSiO₂) ⁽²⁾FC430: surfactant commercialized by 3M Company ⁽³⁾Tyzor:

⁽⁴⁾UVI-6974 Mixture of:

and

[0160] 4. Impact-Resistant Primer Coating Compositions (Primer CoatingCompositions)

[0161] Several primer coating compositions were made by mixing thevarious components as indicated below: Component Parts by weight ImpactPrimer Coating Composition n° 1a (UV curable Acrylic) Tetraethyleneglycol diacrylate (SR- 12.42 268) Aliphatic urethane triacrylate(EB-265) 16.87 n-propanol 20.27 Dowanol PM ⁽⁵⁾ 20.27 Dowanol PnP ⁽⁶⁾20.27 Coupling agent 9.00 ITX ⁽⁷⁾ 0.063 Irgacure 500 ⁽⁸⁾ 0.60 SurfactantFC-430 (50% dilution) 0.21 Impact Primer Coating Composition n° 1b (UVcurable Acrylic) Polyethylene (400) glycol diacrylate 12.42 (SR-344)Aliphatic urethane triacrylate (EB-265) 16.87 n-propanol 20.27 DowanolPM 20.27 Dowanol PnP 20.27 Coupling agent 9.00 ITX 0.063 Irgacure 5000.60 Surfactant FC-430 (50% dilution) 0.21 Impact Primer CoatingComposition n°2 (thermal curable polyurethane latex W-234) PolyurethaneLatex W-234 ⁽⁹⁾ 35.0 Deionized Water 50.0 2-Butoxy Ethanol 15.0 Couplingagent 5.0 or Polyurethane Latex W 234 40.0 Deionized Water 40.0 DowanolPnP 20.0 Coupling agent 5.0 Surfactant L77 ⁽¹⁰⁾ 0.5 Impact PrimerCoating Composition n° 3 (Thermal curable, Acrylic latex A-639) Acryliclatex A-639 ⁽¹¹⁾ 40.0 Deionized water 40.0 2-Butoxy Ethanol 20.0 ImpactPrimer Coating Composition n° 4 (UV curable Hybrid) UVR6110 ⁽¹²⁾ 13.00HDODA ⁽¹³⁾ 10.89 Pentaerithritol pentaacrylate 30.36 GE 21 ⁽¹⁴⁾ 30.29Diethylene glycol diacrylate 7.01 Isobornyl acrylate 2.29 Surfactant0.09 Mixed triarylsulfonium 0.30 hexafluoroantimonate salts ImpactPrimer Coating Composition n° 5 (UV curable Hybrid) UVR6110 13.00 HDODA10.89 Polyethylene glycol (400) diacrylate 30.36 GE 21 30.29 Diethyleneglycol diacrylate 7.01 Isobornyl acrylate 2.29 Surfactant 0.09 Mixedtriarylsulfonium 0.30 hexafluoroantimonate salts

[0162] 5. Optical Substrate Compositions The following mixture wasprepared at 40° C. in the dark. Component Parts by weight Opticalsubstrate composition n° 1 (UV/Thermally curable) Tetraethoxy bisphenolA dimethacrylate 980 Methyl butene-1 ol 20 Irgacure 1850⁽¹⁵⁾ 1.75Optical substrate composition n° 2 (UV/Thermally curable)Polypropyleneglycol (400) 51 dimethacrylate Urethane methacrylate(Plex ® 66610) 34 Isobornyle methacrylate 15 Irgacure 1850⁽¹⁵⁾ 0.1Optical substrate composition n° 3 (UV/Thermally curable)Thiomethacrylate⁽¹⁶⁾ 70 Dicyclopentadiene dimethacrylate 10 FA321M⁽¹⁷⁾20 Methylbutene-1 ol 0.3 UV 5411⁽¹⁸⁾ 0.1 Irgacure 819⁽¹⁹⁾ 0.1⁽¹⁵⁾Irgacure 1850: mixture (50/50 by weight) of:

⁽¹⁶⁾Thiomethacrylate: Plex 6856 sold by RÖHM. ⁽¹⁷⁾FA 321M:

⁽¹⁸⁾UV 5411: 2-(2-hydroxy-5-t-octylphenyl)benzotriazole. ⁽¹⁹⁾Irgacure819: photoinitiator of formula:

[0163] 6. Preparation of the Mold

[0164] Unless otherwise stated, the polycarbonate molds used in theexamples were prepared as follows:

[0165] a) The injection-molded polycarbonate mold is de-gated and thenedged. The edging process may create scratches on the surface of themold, so tape covering of at least the central portion of the moldsurface is used during edging.

[0166] b) After edging, the mold is wipped, cleaned in ultrasonicsystem, and then heated in a clean oven for half an hour at 100° C.

[0167] 7. Deposition of Hydrophobic Top Coat and Anti-Reflecting Coating

[0168] Unless otherwise stated, hydrophobic top coat and anti-reflectingcoating were deposited on the optical surface of the front part of themold as follows:

[0169] The hydrophobic top coat and anti-reflecting treatments areaccomplished in a standard box coater using well known vacuumevaporation practices.

[0170] a—The mold is loaded into the standard box coater such as aBalzers BAK760 and the chamber is pumped to a high vacuum level.

[0171] b—Hydrophobic top coat, fluorosilazane (Shin Etsu KP801M), isdeposited onto the optical surface of the first part of the mold using athermal evaporation technique, to a thickness in the range of 2-15 nm.

[0172] c—The dielectric multilayer anti-reflecting (AR) coating,consisting of a stack of high- and low-index materials is thendeposited, in reverse of the normal order. Details of this depositionare as such:

[0173] c1—The first oxide layer in the antireflecting stack to bedeposited is SiO₂. This SiO₂ layer is created in a two-stage process. Inthe first stage, 2-12 nm of SiO₂ is deposited, by vacuum evaporation,directly on the hydrophobic material with no extra energetic assistanceduring deposition. The SiO₂ deposition is then temporarily halted.

[0174] c2—After this first amount of SiO₂ has been deposited, the ionsource is once again turned on, such that the surface of the SiO₂ is ionbombarded with energetic ions of argon gas, oxygen gas, or a mixture ofthe two gases.

[0175] c3—While the surfaces of the lenses are ion bombarded, depositionof SiO₂ is restarted. Because this second stage of SiO₂ deposition isaccomplished concurrently with energetic ion bombardment from the ionsource, the SiO₂ deposition is considered “ion-assisted”. This secondstage of SiO₂ film growth deposits approximately of 68-98 nm ofmaterial. Thus, the total thickness the first of SiO₂ layer (createdfrom these two stages of SiO₂ deposition) is 80-110 nm (opticalthickness about 100 to 160 nm).

[0176] c4—After the first SiO₂ layer deposition sequence isaccomplished, the remainder of the four-layer anti-reflecting coating isdeposited, in reverse of the normal order, using standard vacuumevaporation deposition techniques, which normally, do not require ionassistance during deposition.

[0177]  The second layer is a layer of ZrO₂ having an optical thicknessof about 160 nm, the third layer is a SiO₂ layer having an opticalthickness of about 30 nm and the fourth layer is a ZrO₂ layer having athickness of about 55 nm (optical thicknesses are given at a wavelengthof 550 nm).

[0178] d—At the completion of the deposition of the four-layeranti-reflecting stack, a thin layer of SiO₂, having a physical thicknessof 1-50 nm, is deposited. This layer is to promote adhesion between theoxide anti-reflecting stack and the subsequent hard-coating which willbe deposited on the coated mold at a later time.

EXAMPLE 1

[0179] The front part of a polycarbonate two-part mold already coatedwith a hydrophobic top coat and an AR coating was coated with HardCoating Composition n° 1. Hard coating application speed was set at 400rpm for 8 seconds and spin off speed at 800 rpm for 10 seconds. HardCoating Composition is cured by IR for 30 seconds with 725F setting,using Lesco IR curing unit. The coated mold was allowed to cool to roomtemperature and Impact Primer Coating Composition n° 1a is applied atthe same speed and timing as mentioned above. Impact Primer Coatingcomposition is cured by UV light, using Fusion system H bulb with beltspeed of (5 feet per minute) 1.526 m/minute.

[0180] Final coating cure was achieved using Lesco IR curing unit set at725F for 30 seconds.

[0181] The coated plastic mold was assembled, filled with opticalsubstrate composition n° 1 and polymerized within 20 minutes. Upondisassembly of the plastic mold, all of the coatings were transferred tothe finished lens.

EXAMPLE 2

[0182] The first part of a polycarbonate two-part mold already coatedwith a hydrophobic top coat and an AR coating was coated with HardCoating Composition n° 1. Hard coating application speed was set at 400rpm for 8 seconds and spin off speed at 800 rpm for 10 seconds. HardCoating Composition cured by IR for 30 seconds with 725F setting, usingLesco IR curing unit. The coated mold was allowed to cool to roomtemperature and Impact Primer Coating Composition n° 1b was applied atthe same speed and timing as mentioned above. Impact Primer CoatingComposition was cured by UV light, using Fusion system H bulb with beltspeed of (5 feet per minute) 1.524 m/minute.

[0183] Final coating cure was achieved using Lesco IR curing set at 725Ffor 30 seconds.

[0184] The coated plastic mold was assembled, filled with opticalsubstrate Composition n° 1 and polymerized within 20 minutes. Upondisassembly of the plastic mold, all of the coatings were transferred tothe finished lens.

EXAMPLE 3

[0185] The front part of a polycarbonate two-part mold already coatedwith a hydrophobic top coat and an AR coating was coated with HardCoating Composition n° 2. Hard coating application speed was 500 rpm for8 seconds and spin off at 1200 rpm for 10 seconds. Hard CoatingComposition precured in a thermal heated oven for 10 minutes at 80° C.The coated mold was allowed to cool to room temperature. Impact PrimerCoating Composition n° 2 was applied at the application speed 400 rpmfor 8 seconds and spin off 1000 rpm for 10 seconds. Impact PrimerCoating was precured at the same temperature and timing as the HardCoating.

[0186] Final coating curing was done in a thermal heated oven for 1 hourat 90° C.

[0187] The coated plastic mold was assembled, filled with opticalsubstrate composition n° 1 and polymerized within 20 minutes. Upondisassembly of the molds, all of the coatings transferred to thefinished lens.

EXAMPLE 4

[0188] The front part of a polycarbonate two-part mold already coatedwith a hydrophobic top coat and an AR coating was coated with HardComposition n° 3, this hard coating did not contain a coupling agent.Hard coating application speed was 500 rpm. for 8 seconds and spin off.at 1200 rpm. for 10 seconds. Hard Coating was precured in a thermalheated oven for 10 minutes at 80° C. The coated mold was allowed to coolto room temperature. Impact Primer Coating Composition n° 2 was appliedat the application speed ⁴⁰⁰ rpm for 8 seconds and spin off 1000 rpm for10 seconds. Impact Primer Coating was precured at the same temperatureand timing as the Hard Coating.

[0189] Final coating curing was done in a thermal heated oven for 1 hourat 90° C.

[0190] The coated plastic mold was assembled, filled with opticalsubstrate composition n° 1 and polymerized within 20 minutes. Upondisassembly of the mold, all of the coatings transferred to the finishedlens.

EXAMPLE 5

[0191] The front part of a polycarbonate two-part mold already coatedwith a hydrophobic coat and an AR coating was coated with Hard CoatingComposition n° 2. Hard coating application speed was 500 rpm for 8seconds and spin off at 1200 rpm. for 10 seconds. Hard Coating wasprecured in a thermal heated oven for 10 min at 80° C. Coated mold wascooled down to room temperature. Impact Primer Coating Composition 3 wasapplied at the application speed 600 rpm for 8 seconds and spin off 1500rpm for 10 seconds. Impact Primer Coating was precured at the sametemperature and timing as Hard Coating Composition n° 2.

[0192] Final coating curing was achieved in a thermal heated oven for 2hours at 90° C.

[0193] The coated molds were assembled, filled with optical substratecomposition n° 1 and polymerized within 20 minutes. Upon disassembly ofthe plastic mold, all of the coatings transferred to the finished lens.

EXAMPLE 6

[0194] The front part of a polycarbonate two-part mold already coatedwith a hydrophobic top coat and an AR coating was coated with HardCoating Composition n° 4. Hard coating application speed was set at 600rpm for 8 seconds and spin off speed at 1200 rpm for 10 seconds. HardCoating was UV cured by Fusion system H bull at (5 feet per minute)1.524 m/minute and followed by 30 seconds IR cure at 725F for 30seconds, using Lesco IR curing unit. Coated mold was allowed to cool toroom temperature and impact Primer Coating Composition n° 4 was appliedat the same speed and timing as mentioned above. Impact Primer Coatingwas cured by UV light, using Fusion system H bulb with belt speed of (5feet per minute) 1.524 m/minute.

[0195] Final coating curing was achieved using Lesco IR curing unit setat 725F for 30 seconds.

[0196] The coated plastic mold was assembled, filled with opticalcomposition n° 1 and polymerized within 20 minutes. Upon disassembly ofthe mold, all of the coatings transferred to the finished lens.

EXAMPLE 7

[0197] The front part of a polycarbonate two-part mold already coatedwith a hydrophobic top coat and an AR coating was coated with HardCoating Composition n° 4, Hard coating application speed was set at 600rpm for 8 seconds and spin off speed at 1200 rpm for 10 seconds. HardCoating UV is cured by Fusion system H bulb at (5 feet per minute) 1.524m/minute and followed by 30 seconds IR cure at 725F for 30 seconds,using Lesco IR curing unit. Coated mold was allowed to cool to roomtemperature and Impact Primer Coating n° 5 was applied at the same speedand timing as mentioned above. Impact Primer Coating was cured by UVlight, using Fusion SYSTEM H bulb with belt speed of (5 feet per minute)1.524 m/minute.

[0198] Final coating curing was achieved using Lesco IR curing unit setat 725F for 30 seconds.

[0199] The coated plastic mold was assembled, filed with opticalsubstrate Composition n° 1 and polymerized within 20 minutes. Upondisassembly of the mold, all of the coating transferred to the finishedlens.

[0200] The performances of the finished lenses of examples 1 to 7 A aregiven in Table below: Bayer Steel Dry abrasion wool Transmission ImpactExample n° adhesion test test test (%) energy (mJ) 1 Well 4.47 1 98.8692.40 Tc = 1.68 mm 2 Well 4.73 1 98.8 1126.60 Tc = 2.56 mm 3 Well 5.350 98.9 711.00 Tc = 1.38 mm 4 Well 4.37 0 98.9 844.00 Tc = 1.46 mm 5 Well4.81 0 97.9 339.80 Tc = 1.48 mm 6 Well 4.22 0 98.8 62.40 Tc = 1.37 mm 7Well 2.66 5 98.6 849.00 Tc = 1.34 mm

EXAMPLE 8

[0201] This example illustrates the use of a protective and releasingcoating on the optical surfaces of the mold.

[0202] The composition of the protective and releasing coating was asfollows: Component Parts by weight PETA LQ (acrylic ester of 5.00pentaerythritol) Dowanol PnP 5.00 Dowanol PM 5.00 n-propanol 5.00 1360(Silicone Hexa-acrylate, Radcure) 0.10 Coat-O-Sil 3503 (reactive flowadditive) 0.06 Photoinitiator 0.20

[0203] The polycarbonate molds are cleaned using soap and water anddried with compressed air. The mold surface are then coated with theabove protecting and releasing coating composition via spin coating withapplication speed of 600 rpm for 3 seconds and dry speed of 1200 rpm for6 seconds. The coating was cured using Fusion Systems H+bulb at a rateof (5 feet per minute) 1.524 m/minute. A hydrophobic top coat and areverse stack of vacuum deposited AR layers are then applied directly onthe above coated molds according to the general procedure describedpreviously. Once AR coating deposition was finished, the molds werecoated first with a hard coating composition n° 1 and then with animpact primer coating composition n° 2, cured, and lenses were cast fromoptical substrate composition n° 1.

EXAMPLE 9

[0204] Example 8 is reproduced except that the mold releasing andprotective coating composition was as follows: Component Parts by weightPETA LQ (acrylic ester of 4.00 pentaerythritol) Dowanol PnP 5.00 DowanolPM 5.00 n-propanol 5.00 1360 (Silicone Hexa-acrylate, Radcure) 2.00Surface active agent 0.06 Photoinitiator 0.20

[0205] The whole stack top coat/AR coating/hard coat/primer releasedwell from the coated polycarbonate mold and a lens having very goodanti-abrasion, antireflective and impact properties was obtained.

EXAMPLE 10

[0206] Example 8 is reproduced except that the mold releasing andprotective coating composition was as follows: Component Parts by weightPETA LQ (acrylic ester of 5.00 pentaerythritol) Dowanol PnP 5.00 DowanolPM 5.00 n-propanol 5.00 Coat-O-Sil 3509 (reactive flow additive) 0.10Photoinitiator 0.20

[0207] The whole stack top coat/AR coating/hard coat/primer releasedwell from the coated polycarbonate mold and a lens having very goodanti-abrasion, antireflective and impact properties was obtained.

EXAMPLE 11

[0208] Example 8 is reproduced except that the molds are coated with thefollowing release coating compositions according to the followingprotocole, before application of the subsequent coatings. Mold coatingcomposition A: Deionized water at 60° C. 0.95 A-1100 (gamma aminopropyltrimethoxy silane) 0.50 Mold coating composition B: Deionized Water at60° C. 0.95 Dow Q9-6346 (3-trimethoxysilyl propyl octadecyl 0.50dimethylammonium chloride)

[0209] The polycarbonate molds were cleaned using soap and water anddried with compressed air. The molds surfaces were treated by dipcoating in the mold coating composition A first for 60 seconds thenrinsed off by 60° C. deionized water; then they were coated by dip withmold coating composition B and also rinsed off with deionized water at60° C. The coating composition B was cured using Blue M convection ovenat 80° C. for 15 min.

[0210] The whole stack top coat/AR coating/hard coat/primer releasedwell from the coated polycarbonate mold and a lens having very goodanti-abrasion, antireflective and impact properties was obtained.

EXAMPLE 12

[0211] Example 8 is reproduced except that the molds were coated with afluorocarbon polymer layer as a releasing coating.

[0212] Polycarbonate molds were prepared by cleaning ultrasonically inwarmed aqueous detergents, then rinsed and dried according to known art.The polycarbonate molds were then heated to 100° C. for a period of timefrom 0.1-3 hours, to fully dry the material.

[0213] The molds were then loaded in the vacuum chamber. The chamber ispumped to a vacuum level. Then, the fluoropolymer Teflon was evaporatedonto the mold surfaces using either resistance or electron beam heating,to a thickness of 2.5 to 150 nm.

[0214] Alternatively, the fluoropolymer layer was applied to the moldsurfaces prior to vacuum deposition by means of spin- or dip-coating,using a dilute solution of soluble fluoropolymers such as Teflon AF,Teflon PTFE FEP, or Teflon PTFE PFA. The thickness of these coatings was30 to 200 nm.

[0215] After deposition of the fluoropolymer layer, the hydrophobic topcoat (KP 801M) and the oxide anti-reflecting multilayer stack weredeposited (in reverse of the normal order), using the process describedabove.

[0216] KP801M hydrophobic material was evaporated on the fluoropolymerlayer using resistance heating. SiO₂ layer, which is the top oxide layerof the AR stack, was then deposited in a two-stage process. The firststage was the deposition of 2-12 nm of SiO₂ without ion bombardment, andthen the balance of the SiO₂ was depositied with argon ion bombardment,to a total SiO₂ thickness of approximately 85 nm. After the SiO₂ layer,the remaining layers of the stack was deposited by standard evaporativeprocesses.

[0217] The layer vacuum deposited final was a thin SiO₂ layer after thestack is completed, to promote adhesion of the AR stack to thesiloxane-based anti-scratch coating. This layer is not optically active,but is included only to enhance adhesion of the vacuum-deposited ARstack to the anti-scratch coating. Thereafter the other layers weredeposited and the lenses cured according to the method described inexample 8.

[0218] The whole stack top coat/AR coating/hard coat/primer releasedwell from the Teflon coated polycarbonate mold and a lens having verygood anti-abrasion, anti-reflecting and impact properties was obtained.

EXAMPLE 13

[0219] Example 3 is reproduced, but using optical substrate compositionn° 2 instead of optical substrate composition n° 1, which is then curedas follows:

[0220] The mold parts are taped in order to produce a cavity and filledusing a syringe, with the optical substrate composition n° 2.

[0221] A pre-cure was made in 15 s using a iron doped mercury UV bulbsupplied by IST, the intensity was 25-30 mW/cm² (measured 420 nanometerwith 0M 2 radiometer).

[0222] Curing was made in IST two side curing oven 2 minutes at 175mW/cm².

[0223] Then curing was achieved in a thermal dynamic air oven, at atemperature of 80° C. for 8 minutes.

[0224] The assembly was edged with the plastic molds in order togenerate a clear interface to help molds taking a part.

[0225] The complete stack was transferred to the lens.

EXAMPLE 14

[0226] Example 13 was reproduced, but using optical substratecomposition n° 3.

[0227] The complete stack was transferred to the lens.

EXAMPLE 15

[0228] Example 14 was reproduced but using an allylic formulation usinga monomer supplied by PPG under CR607 trade name, catalyzed with 3% byweight of IPP (diisopropylperoxide) and cured using a thermal cyclerising the temperature from 35° C. to 85° C. in 16 hours.

[0229] The stack was once against transferred to the lens.

EXAMPLE 16

[0230] Example 13 was reproduced but using an optical substratecomposition which comprises 52 g of 1,2-bis (2-mercapto ethylthio)-3-mercaptopropane with KSCN catalyst 190 ppm mixed with 48g ofxylylene diisocyanate.

[0231] A gel is obtained at room temperature in 5 minutes, curing isachieved at 120° C. during 2 hours in air oven.

[0232] The transfer is made and a very good adhesion is found.

[0233] The performances of the lenses of examples 13 to 15 are given inTable II below. TABLE II Example Bayer Steel wool Dry Transmission n°abrasion test test adhesion (%) 13 5.6 2 Medium 98.9 14 7.1 9 Good 97.715 6.2 0 Good 99.1

[0234] Bayer abrasion resistance was determined by measuring the percenthaze of a coated and uncoated lens, before and after testing on anoscillating sand abrader as in ASTM F 735-81. The abrader was oscillatedfor 300 cycles with approximately 500 g of aluminum oxide (Al₂O₃) ZF152412 supplied by Specially Ceramic Grains (former Norton Materials)New Bond Street; PO Box 15137 Worcester, Mass. 01615-00137. The haze wasmeasured using a Pacific Scientific Hazemeter model XL-211. The ratio ofthe uncoated lens haze (final-initial) is a measure of the performanceof the coating, with a higher ratio meaning a higher abrasionresistance.

[0235] Steel wool scratch resistance was determined as follows

[0236] The lens was mounted coated surface up with double sided tape onthe end of a one inch (2.54 cm) diameter pivoting rod. Steel wool (000grade) was then pressed against the coated surface with a five pounds(2.267 kg) weight as back-pressure. The lens was then oscillated for 200cycles against the steel wool (one inch (2.54 cm) travel), and the hazemeasured. The difference in haze (final-initial) as measured on aPacific Scientific Hazemeter model XL-211 is reported as the woolscratch resistance value.

[0237] Coating adhesion was measured by cutting through the coating aseries of 10 lines, spaced 1 mm apart, with a razor, followed by asecond series of 10 lines, spaced 1 mm apart, at right angles to thefirst series, forming a crosshatch pattern. After blowing off thecrosshatch pattern with an air stream to remove any dust formed duringscribing, clear cellophane tape was then applied over the crosshatchpattern, pressed down firmly, and then rapidly pulled away from coatingin a direction perpendicular to the coating surface. Application andremoval of fresh tape was then repeated two additional times; The lenswas then submitted to tinting to determine the percentage adhesion, withtinted areas signifying adhesion failures.

[0238] Coating passes adhesion tests when percentage adhesion is morethan 95%.

[0239] Transmission was measured using a BYK GARDNER Hazeguard plushazemeter catalog n° 4725.

[0240] Impact energy was measured using a proprietary system. It can bemeasured by using the protocol of the FDA drop ball test with increasingweights for the ball up to the breaking of the lens or the appearance ofa visual crack, generally having the shape of a star, where the ballimpacted. The corresponding energy is then measured.

1. A method for transferring a hydrophobic top coat onto an opticalsubstrate comprising the steps of: (a) providing a two-part plastic moldhaving opposed optical surfaces defining therebetween a molding cavity;(b) forming on at least one of the optical surfaces of the mold ahydrophobic top coat; (c) filling the molding cavity with an opticalsubstrate, liquid, curable composition; (d) curing the liquid curablecomposition, and (e) disassembling the two-part mold for recovering acoated optical article comprising an optical substrate having depositedand adhered on at least one of its faces.
 2. The method of claim 1,wherein the hydrophobic top coat is made of a silicone or afluorosilicone.
 3. The method of claim 1, wherein the hydrophobic topcoat has thickness ranging from 2 to 15 nm.
 4. The method of claim 1,wherein the two-part mold is made of a plastic material selected fromthe group consisting of polycarbonates, polyamides, polyimides,polysulfones, copolymers of polyethylene terephtalate and polycarbonate,crystal polyethylene terephtalate, glass fiber reinforced polyethyleneterephtalate and polynorbornenes.
 5. The method of claim 1, wherein theplastic material is polycarbonate.
 6. The method of claim 1, wherein theplastic material of mold comprises a release agent.
 7. The method ofclaim 6, wherein the release agent is selected from the group consistingof trimethylchlorosilane. chloromethyltrimethylsilane,chloropropyltrimethylsilane, chloromethyl dodecyldimethylsilane,chlorine terminated polydimethylsiloxane,(3,3-dimethylbutyl)dimethylchlorosilane, hexamethyldisilazane,octamehyl-cyclotetrasilozane, aminopropyldimethyl terminatedpolydimethylsiloxane, 3-trimethoxysilyl propyl octadecyldimethylammonium chloride, tetradecyldimethyl (3-trimethoxysilylpropyl)ammonium chloride, trimethylethoxysilane and octadecyltrimethoxysilane.8. The method of claim 1, further comprising, prior to step (b), a stepof forming a protective coating on the optical surface of the mold. 9.The method of claim 8, wherein the protective coating is selected from:UV cured acrylic layer; an amine containing polysiloxane layer; afluorocarbon polymer layer; a vacuum deposited magnesium fluoride layer.10. The method of claim 1, further comprising, prior to step (c ), thestep of forming an anti-reflecting coating on the hydrophobic top coat.11. The method of claim 10, wherein the anti-reflecting coatingcomprises a stack of dielectric material layers of alternate high andlow reflective indices.
 12. The method of claim 11, wherein the layersare vacuum deposited.
 13. The method of claim 11, wherein the firstdielectric material layer deposited directly on the hydrophobic top coatis deposited using a two-stage process in which, in a first stage, afirst sub-layer of dielectric material is deposited by vacuum depositionand thereafter a second sub-layer is deposited by ion assisted vacuumdeposition.
 14. The method of claim 13, wherein the first dielectricmaterial is SiO₂.
 15. The method of claim 10, wherein the stack ofdielectric material layers is a four layer SiO₂/ZrO₂/SiO₂/ZrO₂ stack.16. The method of claim 13, wherein the thickness of the first sub-layerranges from 2 to 12 nm and the thickness of the second sub-layer rangesfrom 68 to 98 nm.
 17. The method of claim 10, further comprising thestep of forming an additional SiO₂ layer onto the anti-reflectingcoating for promoting adhesion to the scratch-resistant coating.
 18. Themethod of claim 10, further comprising forming a scratch-resistantcoating onto the anti-reflecting coating.
 19. The method of claim 18,wherein the scratch-resistant coating is formed by curing a compositioncomprising as main constituents an epoxyalkoxysilane, adialkyldialkoxysilane and colloidal silica or a hydrolyzate thereof. 20.The method of claim 19, wherein the scratch-resistant coatingcomposition further comprises an effective amount of a coupling agentwhich is a pre-condensed solution of an epoxyalkoxysilane and anunsaturated alkoxysilane.
 21. The method of claim 20, wherein theepoxyalkoxysilane is selected from the group ofγ-glycidoxypropyltrimethoxy silane,γ-glycidoxypropylpentamethyldisiloxane,γ-glydicoxypropylmethyldi-isopropenoxysilane,(γ-glycidoxypropyl)methyldiethoxysilane,γ-glycid-propyldimethylethoxysilane,γ-glycidoxypropyldiisopropylethoxysilane and(γ-glycidoxypropyl)bis(trimethylsiloxy)methylsilane.
 22. The method ofclaim 20, wherein the unsaturated alkoxysilane is selected for the groupconsisting of tris (2-methoxyethoxy)silane, vinyl tris-isobutoxysilane,vinyl tri-t-butoxysilane, vinyltriphenoxysilane, vinyltrimethoxysilane,vinyltriisopropoxysilane, vinyltriethoxysilane, vinyltriacetoxysilane,vinylmethyldiethoxysilane, vinylmethyldiacetoxy-silane,vinylbis(trimethylsiloxy)silane, vinyldimethoxyethoxysilane,alkyltriethoxysilane, alkyltriethoxysilane andallyltris(trimethylsiloxy)silane,3-acryloxypropyltris(trimethysiloxy)silane,3-acryloxypropyltriethoxysilane, acryloxypropylmethyldimethoxysilane,3-acryloxypropylethylbis(trimethyl-siloxy)silane,3-acryloxypropyldimethylethoxysilane,n-(3-acryloxy-2-hydroxypropyl)-3-aminopropyltriethoxysilane,3-methacryloxypropyltris(vinyldimethyxyl-siloxy)silane,3-methacryloxypropyltris(trimetholsiloxy)silane, 3-methacryloxypropyltris(methoxyethoxy)silane, 3-methacrypropyltrimethoxysilane,3-methacryloxypropylpentamethyldisiloxane,3-methacryloxypropylmethyl-dimethoxysilane,3-methacrylpropylmethyldiethoxysilane,3-methacryloxypropyldimethylmethoxysilane,3-methacryloxypropyldimethylethoxysilane,3-methacryl-propenyltrimethoxy-silane and 3-methacryloxypropylbis(trimethyl-siloxy)methylsilane.
 23. The method of claim 18, furthercomprising forming an impact-resistant primer coating onto thescratch-resistant coating.
 24. The method of claim 23, wherein theimpact-resistant primer coating is formed by curing a poly(meth)acrylicbased composition or a polyurethane based composition.
 25. The method ofclaim 24, wherein the compositions are latexes.
 26. The method of claim24, wherein the impact-resistant primer coating composition comprises aneffective amount of a coupling agent which is a pre-condensed solutionof an epoxyalkoxysilane and an unsaturated alkoxy silane.
 27. The methodof claim 26, wherein the epoxyalkoxysilane is selected from the group ofγ-glycidoxypropyltrimethoxysilane,γ-glycidoxypropylpentamethyldisiloxane,γ-glydicoxypropylmethyldiisopropenoxysilane,(γ-glycidoxypropyl)methyldiethoxysilane,y-glycidoxypropyldimethylethoxysilane,γ-glycidoxypropyldiisopropylethoxysilane and(γ-glycidoxypropyl)bis(trimethylsiloxy) methylsilane.
 28. The method ofclaim 27, wherein the unsaturated alkoxysilane is selected for the groupconsisting of tris (2-methoxyethoxy)silane, vinyltrisisobutoxysilane,vinyltri-t-butoxysilane, vinyltriphenoxysilane, vinyltrimethoxysilane,vinyltriiIsopropoxysilane, vinyltriethoxysilane, vinyltriacetoxysilane,vinylmethyldiethoxysilane, vinylmethyldiacetoxy-silane, vinylbis(trimethylsiloxy)silane, vinyldimethoxyethoxysilane,allyltriethoxysilane, alkyltriethoxysilane andallyltris(trimethylsiloxy)silane,3-acryloxypropyltris(trimethysiloxy)silane,3-acryloxypropyltriethoxysilane, acrylpropylmethyldimethoxysilane,3-acryloxypropylethylbis(trimethylsiloxy) silane,3-acryloxypropyldimethylethoxysilane,n-(3-acryloxy-2-hydroxypropyl)-3-aminopropyltriethoxysilane,3-methacryloxyltris(vinyldimethylsiloxy)silane, 3-methacryloxypropyltris(trimethylsiloxy)silane, 3-methacryloxypropyl tris(methoxyethoxy)silane,3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylpentamethyldisiloxane, 3-methacryloxypropylmethyldimethoxysilane,3-methacryloxypropylmethyldiethoxysilane,3-methacryloxypropyldimethylmethoxysilane,3-methacryloxypropyldimethylethoxysilane,3-methacryloxypropenyltrimethoxysilane and 3-methacryloxypropylbis(trimethylsiloxy)methylsilane.
 29. The method of claim 1, wherein theoptical substrate is a substrate resulting from the polymerization of:diethyleneglycol bis (allylcarbonate) based compositions, (meth)acrylicmonomer based compositions; thio(meth)acrylic monomer basedcompositions; polythiourethane precursor monomer based compositions; orepoxy and/or episulfide monomer based compositions.